Add a second tote solely for the fish. (leave the lid off of this tote). Obviously both containers are to be at the same level. Run a tube with required o-rings and threaded connectors between totes. Place halfway between bottom and water level, in case of a failure, not all of the water will drain out. Make sure this setup is watertight and ready before adding fish. Water will transfer passively. A second air pump and a aeration stone is required in this setup.

To make this system even fancier, have a pipe with a diameter enough for fish to travel between both totes.

Alternatively like in typical aquaponic systems, use a pump to periodically transfer water between totes.

Other tweaks include: having separate timers for the air-lift pumps, water pumps, and lighting. Running DC made components on solar power is another tweak.